EP0140929B1

EP0140929B1 - Enema bag

Info

Publication number: EP0140929B1
Application number: EP84901564A
Authority: EP
Inventors: Peter Wyville Field
Original assignee: Field Group Research Pty Ltd; Field Group Chemicals Pty Ltd
Current assignee: Field Group Chemicals Pty Ltd
Priority date: 1983-04-13
Filing date: 1984-04-13
Publication date: 1989-02-01
Also published as: WO1984004037A1; EP0140929A1; US4636412A; EP0140929A4; CA1241886A

Abstract

A container useful for both storage and administration of a liquid medical composition for example a barium enema the container comprising a flexible wall (1) and having a port (10) adapted for connection to a tube and the flexible wall being a composite including an innermost layer (11) which is inert to the content and is heat sealed with the port and a non-innermost layer (12) which is resistant to water vapour transmission, the composite having an impact resistance (as measured by ASTM D1909-75 Method A) in excess of 1.2 kg and preferably a resistance to tear propagation (as measured by ASTM D1922, Elmendorf) in excess of 50g/mil.

Description

Technical field

This invention relates to a container useful for storage and administration of medical compositions.
For various medical procedures it is necessary to dispense a liquid composition from a reservoir via a tube to a patient or to transfer a composition from a patient to a reservoir via a tube. Examples involving such procedures include the administration of saline solutions from a reservoir to a patient, the continuous collection of urine for analysis in a pouch reservoir and the administration of a barium enema prior to radiography from an enema bag.
The specialized reservoirs used for administration of solutions and suspensions have in common that they are provided with at least one integral delivery tube or means for connection to a delivery tube. Usually they have been provided in addition with a filling port and have been made from glass, rubber, PVC and even metal according to administration requirements. The reservoirs and associated fittings are manufactured in many forms and sizes each adapted to serve a particular function. Some are part of highly specialized apparatus. Others are simple PVC or polyethylene bags with integral tubular fittings.
European Patent Application EP-A-0069807 describes a synthetic bag-type container for human blood and its fractions, perfusion solutions, dialysis solutions and alimentary and chemical and biological liquids in general, which consists of a thin flexible walled casing which is in the form of a rectangular envelope having a bellows-shaped base and obtained from a single synthetic film sheet. Delivery nozzles project from the base. The synthetic film sheet from which the bag is made may be of a single or double layer type. Double layer sheets are described having a polyethylene, polypropylene or polyethylene-butyl rubber copolymer film bonded to a nylon or polyester film.
European Patent Application EP-A-0096191 discloses a sachet for infusion solutions made of a laminated plastic in two or more layers, with an inner layer of polyethylene or polypropylene and an outer layer of polyamide. In manufacture, a tube of thermoplastic material is blown at an extrusion temperature of about 170°C under aseptic conditions and laminated to other layers of film. With the tube hermetically sealed, the two walls of the tube are welded to form the sachet, which is then trimmed externally. Between the outer film of polyamide and the inner filni there may be a further layer comprising a different thermoplastic material.
Compositions administered are liquids, which term as herein used includes solutions, suspensions and emulsions. Traditionally the compositions were made up immediately prior to use although nowadays many of the required compositions are prepared in bulk by specialist manufacturers, packaged in unit dose or other convenient package size and marketed. Typically the marketed compositions are packaged in glass bottles for sale. Such compositions when purchased are transferred shortly prior to use from the container in which purchased to the reservoir from which they are to be administered via a reservoir filling port or other opening of the reservoir.
Hitherto reservoirs of the type used for administration of such compositions have not been used by manufacturers of the compositions as a package or container in which to market their product. Likewise samples collected in such apparatus have been transferred to other containers for long term storage. That is partly because the specialized reservoirs are of too costly a construction to be used as storage containers or as packaging but more importantly because storage and handling in commerce imposes requirements different from those of medical administration. In practice compositions of the kind under consideration may be stored for periods as long as 12 months in the package prior to use. The package container must be inert to the content for at least that period and must be able to withstand the rigours of handling and transport without leakage or damage. For commerce the package should be of a size, shape and weight which permits economical handling and is of acceptable manufacturing cost. Importantly there must be substantially no water vapour loss which would allow concentrations to alter during storage.
Likewise the packages or containers in which such liquid compositions have been marketed have hitherto been unsuitable for dispensation of contents to, or collection of samples from, patients via a tube. That is not only because the container lacks a suitable shape and/or fittings but because the material of which the packaging container was made have either been unsuitable for the construction of specialized reservoirs for medical use or have other disadvantages in practice. Glass reservoirs are dangerous to pressurize and suffer from a number of disadvantages including fragility, high cost, high weight, inflexibility.
The disadvantages of prior art may conveniently be exemplified by reference to enema bags such as used for administration of a barium enema prior t6 single or double contrast radiography.
A conventional enema bag is an elongate, generally tubular, reservoir having a filling port at one end and provided at the other end with a delivery tube or means such as a spigot for connection with an enema delivery tube whereby the reservoir is placed in communication with a rectal tip adapted for introduction of the reservoir contents into the rectum of a patient.
The enema delivery tube is usually provided with a valve or clamp between the reservoir and the rectal tip. The reservoir filling port is provided with a closure.
For use in double contrast radiography of, for example, the colon an additional requirement is that the bag be capable of being pressurised. After the colon has been filled with the barium enema, the colon is drained leaving a film on the colon wall and air from the bag is usually admitted to inflate the colon. For that purpose the enema bag and filling port closure must be pressure tight. Enema bags made from rubber and stainless steel vessels have been preferred for pressure resistance but are not transparent.
Hitherto compositions for use as a barium enema have been prepared immediately prior to use by dispersing barium sulphate in a required quantity of water or have been purchased as a predispersed suspension of barium sulphate in water. In either case the dispersion is first made up to a required solids content and then admitted from the preparation vessel or storage container via the filling port into the enema bag. As hereinafter used the term "barium enema" refers to a suspension in liquid and not to a dry powder.
As considerable time is required to prepare a suspension from dry powder the use of the predispersed barium enemas is generally most convenient but some adjustment of concentration or viscosity is often desired by the radiographer prior to administration, as dictated by the method of patient preparation or suspected pathology.
Predispersed barium enemas marketed in glass bottles have not avoided the inconvenience of transfer to a flexible enema bag prior to use. It would be desirable to provide an enema bag at sufficiently low cost as to render it disposable and suitable to be pre-packed with a barium suspension.
We have now found it possible to provide an improved container suitable for the storage and/or transport in commerce of a liquid intended to be transferred to a patient via a tube.
More particularly, we have found it possible to provide a container useful in medical procedures which is suitable for transport and/or long term storage of a liquid composition and which is adapted to facilitate dispensation to, or reception from, a patient of the composition via a tube.

Disclosure of the invention

According to one aspect, the invention provides a container for handling and storage of a liquid and for facilitating transfer to or from a patient of the liquid during a medical procedure, said container comprising:

a transparent composite flexible wall or walls,
port means for communication with the interior of the container,
the composite wall including an innermost layer which is substantially inert towards the liquid and which is heat sealed with the port means,
a first non-innermost moisture barrier layer formed from polyvinylidene chloride, high density polyethylene, polyvinyl chloride or polypropylene,
and a second non-innermost layer resistant to water-vapour transmission,
the composite having an impact resistance (as measured by ASTM D1709-75 Method A) in excess of 1.20 kg, and a water vapour transmission rate of less than 7.7 g/m²/24 hours when measured at 37.8°C and 90% RH.

In one embodiment, the invention provides a reservoir useful in the dispensation to or reception from a patient via a tube of a liquid composition or suspension and which avoids at least some of the disadvantages of the prior art. Desirably the reservoir should be capable of construction at a sufficiently low cost as to be disposable.
By way of example only an embodiment of the invention will now be described with reference to the accompanying drawings wherein:-

Brief description of the drawings

Fig. 1 shows a view of an enema bag according to the invention in front elevation.
Fig. 2 shows a cross-section of the enema bag taken on line 2-2 of Fig. 1.

Description of preferred embodiments

The embodiment described is an enema bag but it will be understood that the invention is applicable to other containers from which, or to which, compositions are supplied via a tube during medical procedures.
The enema bag comprises a flexible pouch made from a substantially water impermeable material. The pouch has two walls (of which only one is seen in Fig. 1) in overlying relationship. Walls 1 are connected at a perimeter 2 to define a sealed volume of, for example, 2/3) litres therebetween.
In the example illustrated, walls 1 are made from a co-extruded plastics film, having an inner layer 11 of linear low density polyethylene ("LLDPE") 40 pm thick and an outer layer 12 of biaxially oriented nylon 18 Ilm thick. Intermediate the inner and outer layers is a layer of high density polyethylene ("HDPE") 60 pm thick. Overlying walls are connected by heat sealing or welding at perimeter 2 of the enclosed space. The outer layer is transparent but accepts printing. The inner layer is transparent chemically inert and free of plasticizers. The intermediate layer is transparent and generally impermeable to water vapour.
A tubular polypropylene port or spout 10 communicates with the interior of the pouch defined by perimeter 2 and is welded with wall 1 at a flange 13 extending radially of spout 10 at the proximate end. Spout 10 at or near the distal end may be provided with a closure (not illustrated), for preference a tamper proof cap, and is threaded for connection to an enema delivery tube after removal from spout 10 of the closure.
Perimeter 2 extends adjacent the left (as viewed in Fig. 1) edge 3 and is spaced by a margin from the top edge 4. Perimeter 2 extends adjacent the right edge 5. The lower portion 7 of perimeter 2 is shaped to drain the enclosed volume towards tubular spout 10 and preferably also to minimize dead volume in the vicinity of the spout.
The spout construction is reinforced by virtue of welds extending along the lower edge 6 and the lower portion of sides 3 and 5.
Upper edge 4 is also provided with an adjacent weld strip 14 spaced apart from the upper portion 15 of the perimeter 2 weld and two slots 20 separated from each other by web 21 may optionally be provided as carrying means for the enema bag.
Web 21 is optionally provided with an eye or eyelet 22 whereby the enema bag may be supported, for example from a hook, in a draining orientation so as to drain contents through a tube connected to spout 10.
The enema bag described has a capacity of for example 2.5-3.5 litres and when partly filled with a diluted 75% w/w barium sulphate suspension has a very considerable weight by virtue of the density of the barium sulphate. In addition the bag may be pressurized in use and should be able to withstand at least 25 KPa internal pressure. Embodiments as described have been tested to 150 KPa. During mixing the pouch may be flexed. It will therefore be understood that the materials, weld strength and general construction should be able to withstand severe conditions without failure.
In the example illustrated the co-extruded film has a negligible water transmission rate and all materials conform with FDA and world health regulations for suitability for food and pharmaceutical contact.
In use the enema bag may be filled with a predetermined quantity of barium enema material, i.e. barium sulphate in aqueous suspension, via spout 10 which is then sealed for preference with a tamper-proof closure. The filled sealed enema bag may then be stored, sold, transported and otherwise handled. The suspension may be maintained in the enema bag without deterioration, conveniently carried e.g. by inserting fingers through slots 20 and may be stored flat.
Water additions may be made, if required, prior to administration of a barium enema by the steps of removal of the closure, addition of a required amount of water, replacement of the closure, and squeezing or agitating the bag to obtain uniform dilution or suspension. The closure may then be removed and, a rectal tip connected by means of a delivery tube having a screw connector adapted for connection to spout 10.
Typically in use for double contrast radiography of the colon, the pouch is first pressurized by introducing air at 10-25 KPa into the bag via the delivery tube.
The bag is conveniently suspended by eye 21 at a suitable height above the patient and the barium enema injected into the colon by drainage from the enema bag in the usual manner and assisted by the air pressure. The bag is subsequently lowered and inverted and the barium suspension is drained from the colon into the bag. The gas in the bag is next used to inflate the barium lined colon for double contrast examination with further pressure being applied by external pressure on the bag, for example by squeezing. The levels in the bag are at all times easily visible.
The enema bag may of course also be used in other procedures in which the colon is pressurized by a gas introduced downstream of the enema bag spout for example into the delivery tube or enema.
It will be understood that containers according to the invention may be designed for uses other than as an enema bag. The shape and volume of the container and disposition of inlets or outlets may readily be altered to suit such other requirements. Other inlet and outlet means, for example spigots or tubes having a breakseal may be substituted for spout 10.
Other wall constructions within the scope of the invention will now be described.
The composite walls may be made for example from coextruded film, laminated films, or from films joined each to the other by fusion or adhesives. The innermost layer is generally selected so as to be chemically inert towards the contents or intended contents of the container and so as to be substantially free from plasticizers which might leach into the contents. The innermost layer should also be able to form a seal with the port flange or with a tubular spiggot or with other tube connectors preferably by heat sealing or welding for example radio frequency welding. Preferably the inner layer is selected from polyolefin polymers for example low density polyethylene ("LDPE"), linear low density polyethylene ("LLDPE"), polypropylene ("PP"), ionomer (a modified polyethylene sold under the trade name SURLIN by Du Pont) or ethylene vinyl acetate ("EVA"). Of these, linear low density polyethylene is most highly preferred for the innermost layer because of its superior heat seal strength, high resistance to tear propagation, chemical inertness and contribution to water vapour transpiration resistance.
For an outer layer nylon and more preferably biaxially oriented nylon, are selected. Nylon has been found to impart high tensile strength and abuse resistance and enables the container to support the contents when hung from a hook. Use of nylon as the outer layer permits the container to be printed and decorated, and confers high dimensional stability, abrasion resistance and scuff resistance to the container. Less preferred plastics which can be substituted for nylon in giving strength to the composite include high density polyethylene and polypropylene, each, of which could be orientated or non-orientated.
It is important that the walls provide a sufficient moisture vapour barrier such that there is no significant change of the composition of contents over the normal storage life of the product. For some purposes a thick film of LLDPE provides a sufficient moisture barrier although PVDC, HDPE, PVC, PP, nitrile or vapour deposited metal may be used. In the latter case a window must be provided for transparency.
The Water Vapour Transmission Rate for various suitable wall composites according to the invention is given in Table I under the conditions specified in American Standard Test Method ASTM E96. It will be understood that a lower temperature and humidity the transmission rate will be a fraction of the rates shown in Table I.
The composition of the walls is selected so that the Water Vapour Transmission Rate (when measured according to ASTM E96) is less than 7.7 g/sq.m/24 hrs. at 37.8°C and 90% RH although preferably the rate is less than 1.4 g/sq.m/24 hrs. at 25°C and 90% RH.
The composition of the walls is selected to have an impact resistance when measured by the technique described in ASTM D1909-75 Method A is in excess of 1.20 Kg.
This method covers the determination of the energy that causes a film to fail under specified conditions of impact of a free falling dart. This energy is expressed in terms of the weight (mass) of a missile falling from a specified height which would result in 50% failure of specimens tested.
. This method employs a dart with a 38 mm (1.5 in) diameter hemispherical head dropped from a height of 0.66 m (26 in). This method may be used for films whose impact resistance require masses of about 50 g or less to about 2 kg to fracture them.
A metallized polyester film of 1.8 mm (70 mil) thickness had a puncture range of 1.1 kg.-1.16 kg under comparable conditions.
The composition of the composite walls is selected so that the resistance to tear propagation (as measured by ASTM D1922 is at least 200 g/mm (50 g/mil) and preferably is greater than 400 g/mm (100 g/ml), more preferably greater than 1600 g/mm (400 g/ml).
The composition of the composite walls is preferably selected so as to have a tensile strength (when measured according to ASTM D882) in excess of 14 MPa (2000 psi) at break and preferably above 48 MPa (7000 psi) at break. Some of the composite compositions described in Table I have a tensile strength of 100 MPa (15000 psi).
Preferred embodiments of containers according to the invention enable a liquid composition to be packaged at a manufacturing plant, transported and handled during commerce and safely stored if necessary for many months prior to use. The packages have dimensional stability and accept printing. Because of their strength and abuse-resistance, the bags do not require a rigid outer protective carton or package and do not burst or split. The water transpiration rate is so low that the contents remain of substantially constant concentration. If a lowered concentration is required the package may conveniently be opened prior to use and the content diluted, the flexibility of the package permitting mixing by squeezing. A tube is readily fitted to the threaded port and contents may thus be administered directly from the container without transfer to another reservoir. The package may be internally pressurized if desired and is transparent and flexible thus facilitating certain medical procedures. The container is of sufficiently low manufacturing cost that it may be considered disposable.
Those skilled in the art will readily appreciate the extent to which the dimensions, materials and construction of the container or reservoir described herein may be varied from the example described without departing from the teaching hereof and such variations are comprehended within the scope of the invention as defined by the claims.

Claims

1. A container for handling and storage of a liquid and for facilitating transfer to or from a patient of the liquid during a medical procedure, said container comprising:

a transparent composite flexible wall or walls,

port means for communication with the interior of the container,

the composite wall including an innermost layer which is substantially inert towards the liquid and which is heat sealed with the port means,

a first non-innermost moisture barrier layer formed from polyvinylidene chloride, high density polyethylene, polyvinyl chloride or polypropylene,

and a second non-innermost layer resistant to water-vapour transmission,

the composite having an impact resistance (as measured by ASTM D1709-75 Method A) in excess of 1.20 kg, and a water vapour transmission rate of less than 7.7 g/m²/24 hours when measured at 37.8°C and 90% RH.

2. A container according to claim 1 wherein the second non-innermost layer is made from nylon, high density polyethylene or polypropylene.

3. A container according to claim 2 wherein the said layer is made from biaxially oriented nylon or from oriented polyethylene or polypropylene.

4. A container according to any one of the preceding claims in the form of a transparent, hollow flat pouch.

5. A container according to any one of the preceding claims wherein the water vapour transmission rate through the composite is less than 1.4 g/m²/24 hours at 25°C and 90% RH.

6. A container according to any one of the preceding claims wherein the tensile strength at break of the composite is greater than 14 MPa (2000 psi) when measured according to ASTM D882.

7. A container according to any one of the preceding claims wherein the tensile strength at break of the composite is greater than 48 MPa (7000 psi) when measured according to ASTM D882.

8. A container according to any one of the preceding claims wherein the tear strength of the composite is greater than 400 g/mm (100 g/mil) when measured according to ASTM 1922.

9. A container according to any one of the preceding claims wherein the innermost layer is formed from a polyolefin selected from low density polyethylene, linear low density polyethylene, modified polyethylene, ethylene vinyl acetate and copolymers thereof.

10. A container according to any one of the preceding claims wherein the first non-innermost layer is of high density polyethylene, and the second non-innermost layer is of nylon.

11. A container according to any one of the preceding claims wherein the bag is provided with a margin having an aperture through it whereby the bag may be hung from a hook.

12. A container according to claim 11 which when hung by a hook extending through the aperture of the margin, is drainable through the port.

13. A container according to any one of the preceding claims provided with a tamperproof closure.

14. A container according to any one of the preceding_claims in the form of an enema bag.

15. A container according to claim 14 containing a barium enema composition.

16. An enema bag comprising a container according to any one of the preceding claims when constructed to withstand an internal pressure in excess of 28 kPa (4 psi).